Abstract: Apparatus for producing plastic film by extrusion includes a plastic extrusion machine having an extrusion screw, a motor for turning the screw, a die connected to the screw barrel outlet, a manifold having an opening receiving the die, a blower delivering cooling air to the manifold, and an infared emitter and detector for monitoring phase transition of the molten plastic material into solidified plastic film in adjusting operation of the apparatus to maintain plastic material phase transition occurrence in a preselected position downstream of the die by either adjusting speed of the blower or adjusting speed of the motor or both.

Abstract: The present invention feeds a plurality of different molten resin jet streams into a T die adapted to produce film members such as plastic films. A plurality of molten jet streams extruded from a plurality of extruders, respectively, are fed from their predetermined directions into one resin feed passage in communication with the T die and combined or united without causing the mixture with each other. The relative positional relationship between the intersurfaces between the adjacent molten resin jet streams defined when the molten resin jet streams are combined or united on the one hand and an elongated discharge port of the T die can be adjusted so that the relative positional relationship between a plurality of extruders and the T die can be freely changed.

Abstract: A method of providing uniform thickness of a synthetic resin film upon molding of the synthetic resin film with a die having a plurality of heating elements arranged adjacent a die lip of the die. The thickness of a film molded by the die is measured by cutting a sample of the molded film in a direction perpendicular to the direction of drawing of the film, and measuring the thickness of the sample in the direction of cutting with a film thickness measuring device. The measured values are then fed to an arithmetic unit. At the arithmetic unit, a corresponding relationship is calculated, based on the measured film thickness values, between a one-sided material portion of the film and the plurality of heating elements, and amounts of heat to be generated by the corresponding heating elements are individually controlled in accordance with the relationship.

Abstract: An apparatus for controlling the thickness of a film molded by a melt extruding method provided with a plurality of cooling means for cooling the vicinity of a die lip close to a plurality of heating means and with many grooved holes in which the heating means are embedded and provided with air holes at the both ends thereof, whereby the temperature can be freely adjusted to the high and low set values in a short period of time, by which the time loss and material loss can be reduced.

Abstract: Disclosed herein is a cooling/guiding method and a cooling/guiding apparatus that will be used when a film of a thermoplastic synthetic resin or the like is to be produced by the inflation method or the T-die method.According to the invention, a thermoplastic synthetic resin film is continuously passed through a section constituted by a single or a plurality of air-introducing members having air intake ports, the air surrounding said film is vacuumed by said air-introducing members so that the pressure differential imparted to the film is balanced, and the film is guided into a predetermined path under the condition where the film is separated away from the air-introducing members.Therefore, the apparatus cools and guides the film without coming into contact thereto, and without cooling the film irregularly and without marring the film, making it possible to markedly increase the film-forming speed and quality of the film.

Abstract: To the end of producing high quality film from thermo-plastic resin through inflation molding, there is provided an air ring which has a plurality of slits for guiding cooling air therethrough onto the film. These slits are defined by a plurality of frusto-conical channel defining bodies which are arranged like a set of nested boxes and are provided with different exit angles at their outlets. Through appropriate distribution of the air outlets for cooling the film, a uniform inflation molding becomes possible, allowing a greater molding speed at the same time. The broader ends of the channel defining bodies are mutually threaded in such a manner that they may be independently adjusted along an axial direction. With additional provision of a retractable annular plate at the outlet of a main cooling air channel and proper adjustment of the channel defining bodies, the air ring may be adapted to molding dies of different diameters.